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Bug 1874 - Texture filtering doesn't work in direct3d
Summary: Texture filtering doesn't work in direct3d
Status: RESOLVED FIXED
Alias: None
Product: SDL
Classification: Unclassified
Component: render (show other bugs)
Version: HG 2.0
Hardware: x86 Windows 8
: P2 normal
Assignee: Sam Lantinga
QA Contact: Sam Lantinga
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2013-05-29 06:17 UTC by Yuri K. Schlesner
Modified: 2013-05-30 23:57 UTC (History)
0 users

See Also:

Attachments
Testcase (3.11 KB, text/x-c)
2013-05-29 06:59 UTC, Yuri K. Schlesner 		Details
Proposed patch (806 bytes, patch)
2013-05-29 07:33 UTC, Yuri K. Schlesner 		Details | Diff
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Description Yuri K. Schlesner 2013-05-29 06:17:21 UTC 
It appears that using SDL_HINT_RENDER_SCALE_QUALITY to use linear or anisotropic filtering doesn't work when using the direct3d driver. If I force the opengl driver then linear filtering works correctly.

I investigated and if I comment out the "if (texturedata->scaleMode != data->scaleMode) {" test inside SDL_RenderCopy in SDL_render_d3d.c then the filter setting take effect. However, the sampler state is being set correctly once (verified using some debug prints in SDL). Furthermore, calling IDirect3DDevice9_GetSamplerState to query the current filter returns the expected value of D3DTEXF_LINEAR or D3DTEXF_ANISOTROPIC, even though rendering takes place using the point filter. If the test is commented out and the sampler state is set every time SDL_RenderCopy is called, then it works correctly.

Since I don't have much knowledge of D3D I don't know what could be causing this odd behaviour.
Comment 1 Sam Lantinga 2013-05-29 06:30:56 UTC 
Can you attach a complete sample program with source and data that shows the problem?
Also, what video card and driver revision are you using?

Thanks!
Comment 2 Yuri K. Schlesner 2013-05-29 06:59:51 UTC 
Created attachment 1154 [details]
Testcase
Comment 3 Yuri K. Schlesner 2013-05-29 07:01:32 UTC 
Doing the testcase I noticed that the filter is correct at first, but when you resize the window it gets set to point filtering (and ID9DD9_GetSamplerState also starts returning point sampling, I missed that during my previous testing.)

So it seems that resizing the windows is resetting the context state and SDL isn't noticing that?
Comment 4 Yuri K. Schlesner 2013-05-29 07:02:52 UTC 
Oh, and this is an Intel HD4000 driver version 9.17.10.2932
Comment 5 Yuri K. Schlesner 2013-05-29 07:33:40 UTC 
Created attachment 1155 [details]
Proposed patch

This patch fixes the problem, it was indeed not restoring the state on a reset. This patch resets scaleMode to D3DTEXF_FORCE_WORD so that the state will be reset next time a draw happens. I'm not sure if I did it at the correct place, but I wasn't able to reproduce the problem anymore.

An alternative solution would be to actually restore the sampler state on reset, but this is a smaller change.
Comment 6 Sam Lantinga 2013-05-30 23:57:27 UTC 
Fix looks good, thanks!
http://hg.libsdl.org/SDL/rev/bbb6b079cfe5